1. Field of the Invention
The present invention relates to technology for reconstructing a skeletal image to enhance a resolution of a medical image.
2. Description of the Related Art
With the advancement to an aging society, a variety of issues such as senior citizens, welfare, and medical care have arisen. Here, osteoporosis has been regarded as a social issue to be urgently solved due to an increase in prevalence and degradation in the quality of life. For example, according to statistical data about the national health care published in 2010, the prevalence of osteoporosis studied for people of 50 or more years old showed 34.8% of women and 7.8% of men, which confirms that one in three among women over 50ties is suffering from osteoporosis. Globally, about 0.2 billions of women have the same issue.
The medical definition for osteoporosis is a progressive bone disease that a bone fracture is highly likely to occur due to a decrease in bone mass and fragility in bone strength by a qualitative change. Here, the bone strength indicates a force of bone against the fracture and is determined based on the bone mass and the bone quality.
The bone mass may be expressed as a bone mineral density (BMD). Clinically, dual energy X-ray absorptiometry (DXA), quantitative computed tomography (QCT), and computed tomography (CT) are utilized to measure the BMD. In this instance, according to a DXA based diagnosis method suggested in the World Health Organization (WHO), abnormalities may be found when 30 to 50% or more of bone mass is lost. Accordingly, the early diagnosis for osteoporosis is difficult.
Recently, the bone strength has been known to be determined based on a BMD and a structural characteristic of spongy bone. Only 64% of mechanical strength of spongy bone can be predicted only using a method of measuring only a BMD. Up to 94% of mechanical strength can be predicted by considering even a skeletal structure. In particular, a network of spongy bone cannot be recovered even with medication once the network is disconnected. In the case of a loss of the same bone mass, a decrease in trabecular connectivity further affects the bone strength compared to a decrease in a trabecular thickness.
Accordingly, both the BMD and the trabecular architecture need to be considered to perform an accurate diagnosis. However, although 50 to 200 μm high resolution that is the average trabecular thickness is required to represent a bone micro-architecture of spongy bone, a medical imaging device according to the related art may not readily provide information about the bone quality such as the bone micro-architecture due to constraints in a resolution. For example, in the case of X-ray based CT, relatively low inspection charge and relatively short inspection time are used compared to magnetic resonance imaging (MRI). However, due to a low resolution of about 600 μm, it is difficult to observe bone micro-tissues. Further, an amount of radiation exposure increases as a resolution increases. In the case of micro CT, bone micro-tissues may be imaged at a resolution of 30 μm, however, may not be readily used for clinical usage due to a high radiation amount. In addition, MRI may image a difference between signals coming from tissues through resonance using photons of a body. However, according to an increase in a resolution of an image, a scanning time increases and noise is degraded, which leads to decreasing a signal to noise ratio (SNR).
Accordingly, there is a need for an imaging technology for providing a high resolution image of 300 μm or less from which a bone micro-architecture is verifiable, without increasing an amount of radiation exposure and a scanning time.